室温钠-硫电池用新型正极材料的设计、制备及性能研究

Developing highly efficient rechargeable batteries is crucial to alleviate the current energy and environmental problems. Due to their high specific energy, high columbic efficiency, and low cost, sodium-sulfur (Na-S) batteries are promising candidates for stationary storage applications including smart grid and uninterruptible power supplies. By employing a ceramic electrolyte, traditional Na-S batteries often operate at a high temperature beyond 300 ºC, which brings serious safety problems. On the other hand, room-temperature Na-S batteries based on liquid electrolyte suffer from low capacity and poor cycling performance due to a low electroconductivity of sulfur and the formation of electrolyte-soluble polysulfide intermediates. Inspired by the advantages brought by hierarchically-structured nano-carbon networks in Li-ion batteries and Li-S batteries, this project intends to employ the concept to improve the performances of sulfur cathode materials in room-temperature Na-S batteries with great prospects. Sulfur composite materials with hierarchically three-dimensional conductive network will be designed, synthesized and investigated as the subjects, and their electrochemical reactions with Na will be studied by using the state-of-the-art chemical and electrochemical characterization methods. By using theoretical calculations, the energy storage mechanism of the battery will be analyzed for a better understanding of the main influencing factors for electrode performances. Through constructing sulfur cathode materials with stable cycling performance and large capacity, prototype room-temperature Na-S batteries with high specific energy are expected, which may underlie for the next generation high-energy rechargeable batteries with sustainable energy storage.

发展高效稳定的二次电池储能技术是应对当前日益紧迫的能源与环境问题的重要手段。在众多二次电池储能体系中，钠-硫电池因其高比能量、高库伦效率、低成本等优势，在智能电网等固定式储能领域内极具应用潜力。然而，传统钠-硫电池由于使用陶瓷电解质，需300 ºC以上工作，存在严重的安全隐患。基于液态电解质的室温钠-硫电池，则受限于硫正极电导率低，放电中间产物易溶于电解液等因素，存在容量低、循环性差等问题。借鉴分级纳米碳导电网络在锂离子电池和锂-硫电池电极材料方面的研究经验，本项目面向具有潜在应用前景的室温钠-硫电池正极材料进行研究，拟设计合成具有分级三维导电网络结构的硫正极材料；利用先进的化学和电化学表征技术研究电极反应过程，并结合理论计算分析其储能机理，揭示影响电极材料性能的主要因素。通过构筑循环稳定的大容量硫正极材料，获得高比能原型室温钠-硫电池，为下一代高比能金属二次电池发展奠定良好的科学基础。

发展高效稳定的二次电池储能技术是应对当前日益紧迫的能源与环境问题的重要手段。在众多二次电池储能体系中，钠-硫电池因其高比能量、高库伦效率、低成本等优势，在智能电网等固定式储能领域内极具应用潜力。然而，传统钠-硫电池由于使用需高温工作的陶瓷电解质，存在严重的安全隐患。基于液态电解质的室温钠-硫电池，则受限于硫正极电导率低，放电中间产物易溶于电解液等因素，存在容量低、循环性差等问题。借鉴分级纳米碳导电网络在锂离子电池和锂-硫电池电极材料方面的研究经验，本项目面向具有潜在应用前景的室温钠-硫电池正极材料进行研究，设计合成具有分级三维导电网络结构的硫正极材料，并配合室温钠离子固态电解质和金属钠负极组装室温钠-硫电池。利用先进的化学和电化学表征技术研究电极反应过程，并结合理论计算分析其储能机理，揭示影响电极材料性能的主要因素。通过构筑循环稳定的大容量硫正极材料，和高电导率、界面稳定的钠离子固态电解质，获得高比能原型室温钠-硫电池，为下一代高比能金属二次电池发展奠定良好的科学基础。